Turkey is quite rich with historical buildings. Depending on various factors like time, increasing air pollution due to technological improvements of the present era together with insufficiency of inspection leads to the formation of damages on these buildings which are part of our historical heritage. Conservation of such buildings which are as important as historical documents should be the first and foremost target of any project. Where maintenance is insufficient, conservation and restoration attempts should replace it. What is necessary in restoration is the use of material which resembles the original material to the closest degree or, producing appropriate material which is compatible with the properties of the original material. The first dimension of the current problem is the insufficiency of resources while the second dimension stems from the lack of proper evaluation of the material to be used in conservation and restoration. This study defines the importance of mortars and plasters along with their history and the reasons of deterioration. In addition, it sets up the information flow of mortar and plaster within a systematic decision making process. The necessary experimental methods for the production of new repair mortar or plaster that can be used in determining the character analysis of original mortar and deterioration morphology are also analyzed. Thus, a method that can be used in the conservation and restoration studies is determined with this paper. (C) 2005 Elsevier Ltd. All rights reserved.